Analytical Modeling of Downlink Power Control in Two-tier Femtocell Networks

Despite the advantages of deploying femtocells into cellular networks, the consequent cross-tier interference has seriously limited the network performance. In the downlink, specially, the strong interference from Femtocell Base Stations (FBSs) to nearby macrocell users (MUEs) causes significant coverage holes. Applying different power control techniques has been heavily discussed in 3GPP as an efficient approach for handling dominant interference scenarios. Instead of relying on system level simulations, this paper proposes an analytical model for evaluating downlink power control at femto-tier based on spatial Poisson Point Process (PPP). Tractable closed-form expressions for the coverage probability of both macrocells and femtocells are obtained. We also derive the average achievable rates of MUEs and femto users (FUEs). Some insights into the power control design are given and can be helpful in practical network deployment.